Year Percent 1998-01-01 49.7769 1999-01-01 45.9045 2000-01-01 36.0000 2001-01-01 32.9000 2002-01-01 39.3082 2003-01-01 39.4303 2004-01-01 37.9927 2005-01-01 36.5040 2006-01-01 23.0557 2007-01-01 31.6912 2008-01-01 30.5491 2009-01-01 36.8872 2010-01-01 33.9433 2011-01-01 34.1290 2012-01-01 41.1266 2013-01-01 44.3525 2014-01-01 44.2341 2015-01-01 44.4507 2016-01-01 45.9324